1. Field of the Invention
The present invention relates to a semiconductor integrated circuit for developing a system using a microprocessor as well as a device for developing an application system and a method for the same, and particularly to a semiconductor integrated circuit for developing a system, a device for developing an application system and a method for the same, which are used for developing an application system using a large scale semiconductor integrated circuit provided with a microprocessor as a core as well as necessary peripheral circuits which are on-chipped on the same board as the microprocessor core.
2. Description of the Related Art
FIG. 8 is a block diagram showing contents of a system block for achieving a particular function using a microprocessor. Referring to FIG. 8, this system includes a microprocessor 10 for controlling the overall system, a ROM 22 storing a program and others for operating the microprocessor 10, a RAM 23 for storing data and others, and an interface 24 for various kinds of input and output.
For development of the application system using the microprocessor 10 shown in FIG. 8, it is generally necessary to develop and verify a hardware of the application system including the microprocessor 10 and to develop and verify a software (program) which operates on the microprocessor 10.
An In-Circuit Emulator (ICE) and a logical analyzer have been used for developing and evaluating hardware. The ICE and software debugger have been used for developing software. Among them, the ICE enables the software (program) to operate on an actual hardware of the application system. Consequently, it is possible to develop and evaluate the software (program) on the actual hardware while carrying out development and evaluation of the hardware.
FIG. 9 shows a schematic structure of the system developing device including the ICE as a major component in the prior art. The system developing device in FIG. 9 includes an application system 25 into which a microprocessor is assembled, an ICE 12 attached to a socket in which the microprocessor used in the application system 25 is to be accommodated, and a host computer 18 for operating the ICE 12 to perform a predetermined operation.
When a microprocessor used in the application system 25 is to be debugged, the ICE 12 is attached, instead of the microprocessor to be used actually, for emulating and thereby debugging the hardware and software.
Meanwhile, in accordance with increase of scale of semiconductor integrated circuits, such a large scale semiconductor integrated circuit has been developed and implemented that includes a microprocessor as a core as well as various peripheral circuits which are on-chipped on the same board as the microprocessor core and include function blocks such as those for decoding addresses, latching data and/or controlling timer, and those for controlling input/output and/or communication processing, which are selected depending on use. FIG. 5 is a schematic block diagram showing a structure of a large scale semiconductor integrated circuit. Referring to FIG. 5, the large scale semiconductor integrated circuit has an large scale semiconductor integrated circuit 1, an I/O terminal 2 of the large scale semiconductor integrated circuit 1, a microprocessor core 3, and various peripheral circuits 4 which include function blocks for decoding addresses, latching data, input/output control, communication processing and others, depending on use. For example, the microprocessor core 3 is formed of the microprocessor 10 shown in FIG. 8 in the event that the same is used as a core.
In the application system shown in FIG. 9, the microprocessor 10 is directly mounted on the application system 25. Meanwhile, in the application system using the large scale semiconductor integrated circuit shown in FIG. 5, the hardware is formed of the large scale semiconductor integrated circuit 1 containing the microprocessor core and mounted on the application system. The software (program) operates on the microprocessor core 3 contained in the large scale semiconductor integrated circuit 1.
However, the ICE which has been used for developing the microprocessor application system in the prior art is used to verify the microprocessor itself shown in FIG. 9. Hence, it does not contain various peripheral circuit 4 and also has the same outer configuration as the microprocessor as well as terminals equal in number to those of the microprocessor. Therefore, an outer size of the socket part of the ICE is generally smaller than that of the microprocessor in many cases. As a result, it is impossible to use the ICE for developing and verifying the hardware of the application system using the large scale semiconductor integrated circuit 1 which has more terminals than the microprocessor in many cases. Also, it is impossible to use the ICE for developing and verifying the software (program) on the actual hardware of the application system.
An example of an ICE overcoming the aforementioned disadvantages is disclosed in Japanese Patent Laying-Open No. 4-342036 (1992). FIG. 10A schematically shows a major portion of the ICE disclosed in the above publication, and FIG. 10B schematically shows an end of a user cable 27 shown in FIG. 10A.
Referring to FIG. 10A, a conventional ICE is attached to the application system 25 via a socket portion 26, a user cable 27 and a printed board 28. The printed board 28 is attached to the socket portion 26 via the user cable 27. An end of the user cable 27 is connected to the in-circuit emulator body (ICE body) shown in FIG. 9.
Referring to FIG. 10B, in a connection corresponding to a portion bearing the microprocessor in the system to be developed, there is provided a printed board 28 bearing a plurality of semiconductor integrated circuit devices (IC1-IC4) including a microprocessor chip corresponding to the system to be developed as well as peripheral circuit chips and various memories. The printed board 28 is connected to the ICE body via the user cable 27.
In the prior art, the ICE is constructed as described above in order to overcome the disadvantages of the ICE used for developing the microprocessor application system. However, this measures require the plurality of semiconductor integrated circuit devices (IC1-IC4) on the printed board 28, resulting in a complicated structure of the printed board 28 at the end of the ICE. Also, it is necessary to change the structure of the printed board at the end of the ICE in accordance with each system to be developed, so that the ICE must be changed according to the developing system, resulting in increase of costs.